HIV-infected patients 21 years of age and older with chronic hepatitis B infection and liver cirrhosis who have received lamivudine treatment for at least 1 year may be eligible for this 48-week study. Candidates will be screened with a complete medical history, blood tests and a 24-hour urine collection. Blood tests include HLA typing (a test of genetic markers on white blood cells that permit specialized immunology studies). Within 4 weeks, candidates who appear eligible for the study will have a physical examination and medical history, an abdominal ultrasound (imaging test using sound waves) to check for cancer of the liver, chest X-ray and electrocardiogram (EKG). Blood and urine tests will also be done, and women who can become pregnant will have a pregnancy test.